Cut away the skin of the grapefruits, remove the white pith. Using a knife, cut in between the membrane to release the segments. Squeeze out the juice from one of the segments just enough to make 1 tablespoon of grapefruit juice. Set aside the juice and the remaining segments.
Make the Vinaigrette: In a jar, add the grapefruit juice, olive oil, white wine vinegar and honey. Put the lid on and shake.
In a small mixing bowl, add the crab meat and stir in 1 tsp of the vinaigrette until crab is evenly coated. Set aside.
Make the Salad: In a large salad bowl, using your hands or two forks, combine the endives, grapefruit and avocado. Drizzle with the vinaigrette and season with salt. Toss to combine.
Divide the salad among bowls. Place a tablespoon of crabmeat on top. Optional: Sprinkle with coarsely ground pink peppercorns.